Vehicles having a high center of gravity, such as minivans, SUVs (sport utility vehicles), or delivery vans, tend to roll over about their longitudinal axes when subjected to high transverse acceleration while traveling along a curve. Therefore, rollover stability systems, such as ROM (rollover mitigation), are often used in such vehicles to stabilize the vehicle in situations which are critical with respect to the driving dynamics and reduce the tipping motion of the vehicle about its longitudinal axis. An electronic stability program having a ROM function, known from the related art, is illustrated as an example in FIG. 1.
FIG. 1 shows a highly simplified schematic block diagram of a known ROM system, which essentially includes a control unit 1 having a ROM control algorithm, a sensor system 2 for detecting a critical rollover driving situation, and an actuator 3 for performing a stabilization intervention. If control unit 1 detects a critical rollover situation on the basis of sensor signals, the system intervenes in the driving operation by actuating the brake on the front wheel external to the curve and via the engine torque. Other systems also intervene in the driving operation via an active suspension/shock absorber system (normal force distribution system), for example.
In a known rollover stability system, a critical rollover situation is typically detected by the fact that a variable describing the transverse dynamics of the vehicle (referred to hereinafter as control variable) is monitored for a threshold value. This means that the variable is compared to a characteristic value, and if the threshold is exceeded, a stabilizing intervention is performed. This control variable is typically also used for determining the intensity of the control intervention.
The control variable is usually a function of the transverse acceleration of the vehicle and of the variation of the transverse acceleration over time. The transverse acceleration is usually measured using a transverse acceleration sensor. Activation and de-activation of the ROM rollover stability regulation is thus related to the transverse acceleration of the vehicle. This has the following disadvantages: If the control variable exceeds the predefined threshold value, a more aggressive stabilization intervention is performed as a function of the transverse acceleration. The measured transverse acceleration of the vehicle and thus the control variable are reduced due to the stabilization intervention. If the control variable drops below a predefined de-activation threshold, the stabilization intervention is terminated. If the vehicle continues to be steered aggressively in this situation while traveling at a high velocity, termination of the stabilization intervention results immediately in another critical rollover situation.